Search dogs were brought in to hunt for other possible victims, and a skip loader was brought in to move the dense, heavy debris. No other victims were found.

The beach is reached by wooden stairs from a parking lot above.

Homes atop the cliff were not in any danger, Encinitas Fire Chief Mike Stein said.

The cliff remained unstable and complicated the search effort, Mr Stein said.

A San Diego County Sheriff's deputy looks on as search and rescue personnel work at the site of a cliff collapse at a popular beach in Encinitas, California. Picture: AP

Suburbs north of San Diego have contended with rising water levels in the Pacific Ocean, pressuring bluffs along the coast.

Some bluffs are fortified with concrete walls to prevent multimillion-dollar homes from falling into the sea.

Long stretches of beach in Encinitas are narrow strips of sand between stiff waves and towering rock walls.

Rescue dogs were used at Grandview Beach. Picture: AP

People lounging on beach chairs or blankets are sometimes surprised as waves roll past them and within a few metres of the walls.

Grandview Beach is fairly narrow, with tides high this week. Surfers lay their boards upright against the bluff.

Cliffside collapses are not unusual as the ocean chews away at the base of the sandstone, authorities said.

A fire truck sits above the site of a cliff collapse at a popular beach in Encinitas, California. Picture: AP

Some beach areas were marked with signs warning of slide dangers.

Several people have been killed or injured over the years in bluff collapses.

The Tribune reported that Rebecca Kowalczyk, 30, of Encinitas died near the same area on January 16, 2000, when a 100-metre-wide chunk of bluff fell and buried her.

Bluffs give way four to eight times a year in Southern California, but "nothing of this magnitude," said Brian Ketterer, southern field division chief of California State Parks.

"This is a naturally eroding coastline," Encinitas Lifeguard Capt. Larry Giles said. "There's really no rhyme or reason, but that's what it does naturally. … This is what it does, and this is how are beaches are actually partially made. It actually has these failures."